Perhaps none was as improbable or memorable as this last one, which made sure a season filled with dramatic endings wouldn’t end just yet.

Seth Smith hit a game-tying, two-run double off Tigers closer Jose Valverde in the ninth inning and Coco Crisp capped Oakland’s rally with a two-out RBI single as the A’s staved off elimination for a second straight night with a 4-3 victory over Detroit in Game 4 Wednesday night.

‘‘This club, we’ve been battling the whole year, giving 100 percent, and these walkoffs have been our MO this year,’’ Crisp said.

The A’s rode a major league-leading 14 walkoff wins in the regular season to an improbable AL West title. Those paled in comparison with No. 15, which set up a win-or-go-home Game 5 against Justin Verlander and the Tigers on Thursday night.

Josh Reddick led off the ninth with a single just under the glove of diving second baseman Omar Infante. Josh Donaldson followed with a double off the wall in left-center and both runners scored on Smith’s double. Two outs later, Crisp lined a single and Smith scored easily when right fielder Avisail Garcia couldn’t handle the ball.

That set off a raucous celebration near first base as the A’s poured out of the dugout to mob Crisp, who was the recipient of a whipped-cream pie that became a custom in this remarkable season in Oakland. This marked the second time the A’s erased a two-run deficit in the ninth inning to win a postseason game, the other coming in Game 5 of the 1929 World Series.

Crisp ended three games with RBIs this season, tied for most in the majors. And like the others, this one ended with Reddick nailing him with a whipped-cream pie during a postgame television interview.

‘‘He’s been our walkoff leader all year,’’ Reddick said. ‘‘Once we got into that situation, I think everybody in the dugout knew he was going to come through for us. Once we get one or two runners on with that situation, we have a really good feeling that we’re going to win the ballgame. He’s been clutch for us in the ninth inning.’’

Ryan Cook retired four batters for the win.

The A’s, who have the lowest payroll in baseball, need just one more surprising result to win their second postseason series since 1990. Rookie Jarrod Parker will take the mound in Game 5 on Thursday night against Verlander, the reigning AL Cy Young winner and MVP.

‘‘That’s why this is the greatest game of all,’’ Tigers manager Jim Leyland said. ‘‘It looked like we were going to get it. We didn’t do it. We didn’t quite get the 27 outs, that’s part of the game. You get tested all the time in this game. And this is a good test.’’

The Tigers looked to be in prime position to advance to their second straight ALCS and have a rested Verlander for Game 1 when they took a 3-1 lead into the ninth behind a strong start from Max Scherzer and a homer from Prince Fielder.

‘‘There’s no ending yet,’’ Oakland closer Grant Balfour said. ‘‘I’m hoping that the ending comes at the end of October. I hope there’s a period at the end of the story. It’s an unbelievable story. It just keeps going. And we’re going to take it out there tomorrow and give it everything, just like we have the last two games. If we can do that then I like our chances.’’

Scherzer, who was dealing with shoulder, deltoid, and ankle injuries late in the season, looked in top form against the A’s. He allowed just one baserunner in the first four innings and struck out seven of the first 15 batters he faced.

A.J. Griffin allowed two runs in five-plus innings. He was the third Oakland rookie pitcher to start a game this series, the most ever by a team in a single postseason. The A’s used just two rookie starting pitchers in 147 postseason games before this year: Joe Bush in the 1913 World Series and Barry Zito in the 2000 division series.

The A’s finally got to Scherzer for an unearned run in the sixth. Crisp reached when Fielder misplayed a hard grounder to first base into a two-base error. Crisp advanced on a wild pitch and scored on Stephen Drew’s double to right-center. But the A’s ran themselves out of a potential big inning when Drew was easily thrown out trying to stretch the hit into a triple.